Some flushing systems suffer from the effects of cross-contamination. The transfer of germs from one user to another can occur when a user touches a handle that enables the flow of water into a fixture. Cross-contamination may result from hand-to-mouth, hand-to-nose, and hand-to-eye contact. An awareness of such contamination can create a reluctance to touch a fixture handle which does not promote good hygiene.
To minimize risk of transferring germs, some flushing systems use hands-free-methods to control water flow. In some systems, a passive sensor is used to detect the presence of a user. Once the user leaves an area, some devices use a rotating device to translate the rotary motion of a motor into a linear motion needed to actuate a handle.
In some rotating driven devices, the inertia of the motor shaft can cause the motor shaft to rotate beyond a desired stopping point and thus initiate multiple water flows through the fixture. Besides wasting water, such over-rotation can fatigue the rotating device and require a higher initial torque to initiate another rotation at the start of a second flushing cycle.